On the relative humidity of the atmosphere

2025/06/30 by Raymond T. Pierrehumbert, Pierrehumbert, Raymond T., Helene Brogniez +3 · 1 voice
Physics and Astronomy · #Atmospheric and Oceanic Physics (physics.ao-ph) #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Geophysics (physics.geo-ph) #astro-ph.EP #physics.ao-ph #physics.geo-ph

paper · pdf · doi:10.48550/arxiv.2507.08824

Abstract

Water vapour is highly subsaturated in much of the Earth's atmosphere. This has important consequences for water vapour feedback, and also for general phenomena such as the runaway greenhouse. In this chapter, we discuss the processes that create subsaturation, with reference to both observations, general circulation models, and a range of idealized theoretical models which produce subsaturation. While this chapter focuses on subsaturation of water vapour in Earth's atmosphere, the processes discussed are generic to condensible substances in all planetary atmospheres.

Citations

• The UVic earth system climate model: Model description, climatology, and applications to past, present and future climates

Discussions

• Newly available paper on processes maintaining subsaturation of condensibles in planetary atmospheres (a blast from the past). arxiv.org/abs/2507.08824 . This paper is applied to water on Earth, but t [bsky, 3 points, 1 comments]

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